If you have the time for it, spend three months in England and it will stick to you without too much effort. I believe there are langauge programs of several months. while you are there learning the language you get a temporary job and they make sure there's enough interaction with native speakers. This is the best solution if you want a genuine English accent... You might want to contact the British embassy on this.

TRY to atleast watch bbc news hour channel daily 2 hours atleast.
then some good english movies!

You have to be born here